Final Flashcards
identify the building blocks of DNA
DNA (Deoxyribonucleic acid) is made up of nucleotides
nucleotides have three parts: a sugar, a phosphate group, and a nitrogenous base
describe DNA’s structure and the rules for base pairing
DNA is in a form of a double helix=two strands of DNA twist together with the sugar-phosphate backbone on the outside and nitrogenous base on the inside. (nitrogenous pairs can only pair: adenine–>thymine and guanine–>cytosine)
explain how the template mechanism is important in DNA replication
the template is important in DNA replication because it allows for a complimentary strand to be made (after the two double helix strands separated) so nucleotides can be added and create a new DNA strand
describe the process of DNA replication. explain the “one gene-one polypeptide” hypothesis
- DNA replication is the process of copying the DNA molecule by separating the two strands of the double helix, they use the separated strands as a template called the complimentary strand in order for nucleotides to be added and so DNA polymerase can form bonds and create a new DNA strand
- states that each gene controls the production of a specific polypeptide (scientists know most genes code for the production of a single polypeptide)
trace the information flow from DNA to protein
first, messenger RNA is transcribed from the DNA molecule. an enzyme called RNA polymerase joins the RNA nucleotides together during transcription. RNA splicing removed introns and joins the exams. then it is transferred to the cytoplasm. transfer RNA binds to the mRNA. the process of bringing amino acid into position on the ribosome (ribosomal RNA)
describe how amino acids are coded
transfer RNA (has an amino acid binding site at one end) binds to the mRNA bringing an amino acid into position to be added to the polypeptide (takes place on a ribosome=ribosomal rna)
describe the process of DNA transcription
the DNA sequence is converted to the form of a single strand RNA molecule
describe how RNA is translated to a protein
in the cytoplasm translation converts the nucleic acid sequence into a sequence of amino acids
summarize protein synthesis
the DNA is transcribed in the nucleus, the introns are removed, the exams enter the cytoplasm as mRNA (by translation) the mRNA binds with the tRNA on a ribosome (rRNA)
describe the types of mutations that can affect genes
mutations=a change in a single nucleotide or a change in a large part of a chromosome
- substitution:one nucleotide is replaced by another
- insertion/deletion: one or more nucleotides are added to/removed from a gene
explain what can cause a mutation
errors in crossing over or DNA replication and also a mutagen (physical/chemical agent that causes a mutation)
describe how DNA is packs within the nucleus
first, DNA molecule wraps tightly around small proteins called histones. next, the DNA and the histones wrap into a tight cool. the coil twists again into a thick structure called a “supercoil”
describe the significance of the human genome project
medical researchers use the data to identify genes associated with diseases and to develop treatment for genetic disorders
relate down syndrome and nonseperation/nondisjunction of chromosomes
trisomy 21 which is when a person has three #21 chromosomes. I normally happens because of nondisjunction which is when a pair of homologous chromosomes or sister chromatids fail to separate during meiosis
describe how chromosomes can be damaged
nondisjunction: pair of homologous chomosomes or sister chromatids that fail to seperate
duplication: occurs when a part of chromosome is repeated
deletion: occurs when a part of a chromosome is lost
inversion: occurs when part of a chromosome is reversed
translocation: occurs when a portion of a chromosome attaches to a non-homologous chromosome
summarize the information provided in a pedigree
used to study the inheritance of traits in a human by tracing the occurence of a trait in a family
explain how recessive, dominant, and sex-linked disorders are inherited
recessive: need both alleles to have the disorder, if you have one you are a carrier and none you don’t have it at all
dominant: only need one allele for the disorder to show, if you have none it won’t show
sex-linked: the allele for the trait is located on the X chromosome. males are more at risk than females
describe how it is possible to predict certain genetic disorders
a genetic counselor is a person who is trained to collect and interpret family histories of genetic disorders
Explain how mutations to genes that play a role in regulating the cell cycle can lead to cancer
a mutation can cause a gene to be cancer-causing (oncogene)
explain how the use of bacteria has contributed to the development of DNA technology
biotechnology: involves changing the genomes of organisms using DNA technology
list some of the recent research trends in recombinant DNA technology
medicine, agriculture, and other fields
explain the role of plasmids in engineering bacteria
they use plasmids to move genes into bacteria
explain how biologists “cut and paste” DNA
a restriction enzyme “cuts” a dna molecule into fragments at specific points. Another enzyme “pastes” a fragment carrying a particular gene into a plasmid
describe the procedure used in cloning a specific gene
a restriction enzyme “cuts” a dna molecule into fragments at specific points. Another enzyme “pastes” a fragment carrying a particular gene into a plasmid. The plasmid is put back into a bacterial cell which then reproduces and creates a clone
identify the usefulness of recombinant microorganisms
they create GMO’s that are used often
describe how biologists genetically modify plants and animals
plants: researchers insert a plasmid containing the desired gene
animals: desired gene is inserted into a fertilized egg. the egg is returned to a female animal’s body
explain a technique used to clone animals/plants
plants: cuttings
animals: replacing the nucleus of an egg cell with another cell’s nulceus
summarize the GMO controversy
some people think they are harmful to human health and the environment but some people think they are safe
describe the technique that enables scientists to mass-produce specific segments of DNA in a test tube
polymerase chain reaction is a technique that makes billions of identical DNA molecules in a few hours
describe a technique used to compare DNA samples
Gell electrophoresis is a technique for sorting DNA fragments by length. the shorter fragments sink to the bottom and the larger fragments stay at the top. they can use this to compare DNA samples
explain how operon enable a prokaryote to respond to changes in the environment
in prokaryotes, clusters of genes are controlled by two short stretches of DNA called control sequences. A cluster of genes, along with its two control sequences, is called an operon
summarize the importance of cellular differentiation in the development of an egg into an organism
in organisms with many cells, individual cells become more specialized in structure and function as the organism develops (cellular differentation)
identify unique features of stem cells
they remain undifferentiated but they are cells with the potential to develop into one of several types of differentiated cells
describe a homeotic gene
master control genes that produce proteins that regulate the expression of other genes
summarize ideas from Darwin’s time that influenced his work
evolution: all of the changes that have transformed life over an immense period of time
adaptation: an inherited characteristic that improves an organism’s ability to survive and reproduce in a particular environment
identify some key observations from Darwin’s voyage that led to his theory
theory: evolution
key observations: variation in birds and other organisms
describe the two main points of Darwin’s theory
descent with modification: species living on earth today descended from earlier species
natural selection: process by which individuals with characteristics well-suited to the environment leave more offspring on average than do other individuals
describe information the fossil record contains about life on Earth
fossil record: the collection of fossils recorded in rock layers over time. fossils of extinct species (species that no longer exist) help scientists reconstruct the past. older fossils=buried deeper
tell how the geographic distribution of organisms relates to evolution
where organisms are distributed throughout the world gives clues to how modern species may have evolved
explain how similarities in structure and development among different species are evidence for evolution
similar structures among related species, called homologous structures, provide clues about evolution. Vestigial structures are homologous structures that have a major function in one species but not in a related species. comparing embryos also give clues to evolution when they were similar in closely related species
describe molecular level for evolution
DNA sequences of different species can also be compared. The more similar the sequences, the more recently the species shared a common ancestor
Summarize Darwin’s theory of natural selection
the process by which individuals with inherited characteristics well-suited to the environment leave more offspring on average than do other individuals
compare and contrast natural selection and artificial selection
natural selection: something that just happens and is the second point of evolution
artificial selection: selective breeding of plants and animals to produce offspring with traits that humans value, we control, and supports evolution
relate pesticide resistance in insects to natural selection
pesticides over time do not work because insects adapt to it so people need to keep altering pesticides
explain the significance of gene pools in understanding evolution
gene pool=consists of all the alleles, or different forms of genes in all the individuals in a population. the frequency of alleles refers to how often it occurs in a gene pool. Populations that do not undergo change to their gene pools are not currently evolving
tell how genetic drift, gene flow, mutation, and natural selection contribute to changes in gene pool
genetic drift: a change in gene pool due to chance
gene flow: the exchange of genes with another population
mutation: a change in an organisms DNA
natural selection: occurs becuase of differences in biological fitness
explain what is meant by the term fitness
the contribution that an individual makes to the gene pool of the next generation compared to the contribution of other individuals
describe recent evidence for microevolution on the Galápagos Islands
microevolution: a generation-to-generation change in the frequencies of alleles within a population
- genetic drift: a change in a gene pool due to chance
- gene flow: the exchange of genes with another population
- mutation: a change in an organism’s DNA
- natural selection: occurs because of differences in biological fitness
explain how natural selection cause the sickle cell allele to persist in some gene pools
because in the African populations need one copy of the sickle cell allele in order to be resistant to malaria
explain how antibiotic resistance may evolve in bacteria
antibiotic drugs kill/slow the growth of bacteria. While the drugs kill most of the bacteria, the resistant bacteria multiply and then become widespread in the population
describe biological species concept
defines a species as a population or group of populations whose members have the ability to breed with one another in nature and produce fertile offspring
distinguish between microevolution and macroevolution
microevolution: small generation-to-generation changes
macroevolution: major evolutionary changes
list types of reproductive barriers between species
different mating seasons, different behaviors used to attract males
speciation
origin of new species
explain how geographic isolation and adaptive radiation contribute to species diversity
geogrphic isolation occurs when a population becomes seperated from the rest of the species due to geographic changes or movement to an isolated place. The isolated population evolves new adaptations to its changed environment. When popoulations of a species evolve adaptations to a variety of different environments and form diverse new species(adaptive radiation)
describe how evolution can refine existing adaptations
some complex structures evolve in small steps from simple structures with the same basic function. Other structures evolved as adaptations for certain functions and later fulfilled a different function
explain how existing structures can take on new functions through evolution
some complex structures evolve in small steps from simpler structures with the same basic function. Other structures evolved as adaptations for certain function and later fulfilled a different function
explain the role of developmental biology in understanding evolutionary change
embryology: the study of how organisms develop from fertilized egg to fully formed organisms
explain how fossils can form
they form from remains of organisms buried in sediment, dust, or volcanic ash (younger fossils layer over older)
describe the geologic time scale
geologic time scale organizes Earth’s history into the Precambrian, Paleozoic, Mesozoic, and Cenozoic eras
summarize methods used to determine the ages of fossils
younger=layered on older (relative age)
absolute age=can be determined with radiometric dating
half-life=time it takes for 50% of the original to decay
describe how continental drift and mass extinction relate to macroevolution
continental drift is the movement of Earth’s continents on large plates of crust. Mass extinction is a great species loss that happened after Pangaea formed. This relates to macroevolution because this caused macroevolution
state the goals of taxonomy
to assign a universal scientific name to each known species and to organize the diversity of life by classifying species into larger groups of related species
describe how evolutionary biology and molecular biology influence classification
cladograms-things with similar structures=closely groups them. Ones with different structures are not grouped as closely
summarize the meaning of a cladogram
phylogenetic trees that specify the derived characteristics of clades, to show relationships among organisms
identify two domains of prokaryotes
archaea: live in extreme environments and complex
bacteria: small and simple
explain how prokaryotes reproduce
binary fission=DNA copies move to opposite ends of the cell when it splits in the middle
explain how prokaryotes recycle chemicals between organic matter and the nonliving environment
- heterotrophic prokaryotes consume complex organic molecules and return carbon to the atmosphere in the form of carbon dioxide
- some species of bacteria convert nitrogen gas in the air to nitrogen compounds in soil/water. It can then be used by plants
describe ways that prokaryotes are helpful to humans
bioremediation: use at organisms to remove pollutants from water, air, and soil
describe the structure and reproduction of viruses
the structure: head with protein coat, DNA/RNA, tail
reproduction: -lytic cycle: attaches to a host cell. Injects DNA. Viral DNA multiplies rapidly. Host cell bursts=releasing hundreds of new viruses that infect new host cells and repeat the cycle.
- lysogenic cycle: attaches to host cell. Injects DNA that adds to the host cells DNA. each time the host cell reproduces to does the virus’ DNA
explain how viruses cause diseases
using the equipment of the host cell
explain how humans defend against viral diseases
good hygiene, immune system, and vaccines`
describe characteristics that all protists have in common
eukaryotic cell structure (membrane, nucleus, organelles)
explain why certain unicellular protists can be considered the most complex of cells
protists one cell must consume/process food, respond to stimuli, excrete wastes, and reproduce. The one cell has to carry out all of an organisms life functions
identify the three types of nutrition among protists
animal-like protists=eat food (ex:protozoans) (heterotroph)
fungus-like protists=feed on decaying matter (heterotroph)
plant-like protists: make their own food through photosynthesis (ex:algae)(autotroph)
explain the functions of spores in fungal reproduction
spores are haploid cells with thick cell walls that function as the dispersal stage in the reproduction of fungi
describe two examples of symbiotic fungi
lichen=mutualistic pairing of a fungus and an algae
mycorrhizae=symbiotic relationship between fungal hyphae and plant roots
identify some fungal diseases of plants and of humans
plants: Dutch elm Disease (eliminated most elm trees in North America)
humans: yeast infections of the lungs, ringworm
describe some human uses of fungi
distinct flavors of cheese, yeast in baking/brewing/wine-making, and antibiotics
explain the role of fungi in recycling organic matter
decomposers that supply ecosystems with essential nutrients for plant growth
relate anatomy and physiology
anatomy is the study of an organism’s structure and physiology is how it functions
identify the levels of structure in the human body
cell–>tissue–>organ–>organ system
identify the four major tissue categories and describe their functions
epithelial tissue: covers surface of the body and lines internal organs
connective tissue: holds together and supports other tissues
nervous tissue: forms the communication system of the body
muscle tissue:
-skeletal muscle: attached to bones and enable various part of the body to move (voluntary)
-cardiac muscle: found in the heart (causes it to beat) (involuntary)
-smooth muscle: found in digestive system and most other organs (involuntary)
define homeostasis and explain its importance
your body protects itself from changes in the outside environment and provides a stable internal environment
explain how homeostasis involves chemical exchange
the body exchanges chemicals with the external environment(exs: body takes in oxygen and realeses carbon dioxide, sweating)
list the main functions and parts of the skeleton
skeleton provides a strong framework that holds up the body and keeps its shape, protects organs, and provides places for muscles to attach
skull=at the top of the skeleton (holds/protects brain)
backbone: consists of small, flat bones (vertebra) that are separated and cushioned by disks made of cartilage (protects spinal cord)
describe the structure of a typical bone
bone matrix (flexible fibers) surrounds bone cells. Cartilage cushions the ends of bones. Bones contain marrow. There is yellow marrow (stores fat) and red marrow (develops blood cells)
compare and contrast the 4 types of joints in your body
ball-and-socket: enables back/forth motion and side/side motion (greatest range of motion)
gliding joint: allow small bones to slide gently over one another
hinge joint: permits movement in a single plane
pivot joint: enables one bone to rotate around another
indentify three disorders of the skeletal system
arthritis: inflammation of joints
osteoporosis: bones become thinner and break easier
cancer
explain how muscles and bones move the body
a muscle is attached to a body by a types of cennected tissue (tendon). As a muscle contracts, it pulls on the attached bone. Muscles work in pairs so when the first muscle contracts the second muscle relaxes and allows the body to move
describe the structure of a skeletal muscle
consist of bundles of muscle finers, along wiht nerves and blood vessels. A muscle fiber is a single long muscle that contains many nuclei. Inside a muscle fiber are bundles of smaller fibers called myofibrils which consist of repeating sacromeres. sacromeres are made up of thin/thick filament proteins (actin/myosin) that slide across one another causing the muscle to contract
describe the basic structure and function of the nervous system
CNS: brain and spinal cord (processes information)
PNS: rest of nervous tissue (carries information to/from the CNS through nerves)
nervous system=three main functions
-sensory input: PNS receives a stimulus or carries information about the stimulus to CNS
-integration: occurs when neurons in the CNS interpret the sensory information
-motor output: occurs when the CNS orders a response and the response is carried away from the CNS
explain the pathway of a reflex arc
it is a survival mechanism that just happens as a reult of an action occuring (an interneuron processes informatioin about sensory input and formulates a response
explain how a neuron at rest stores potential energy
- when a neuron is not transmitting a signal, its plasma membrane keeps opposite charges apart, creating a “resting potential” until a nerve signal is transmitted
- the voltage moves inside/outside/across the neurons membrane
relate how a nerve signal begins, travels, and crosses synapses
- neurotransmitters release from one cell and allow it to enter the next
- the synapse is the junction between an axon of a sending neuron and the receiving neuron. It includes the membranes of both cells and the space between, called the synaptic cleft. When the neuron is stimulated. Na+ ions flow into the cell. The inside becomes positive. The K+ ions then flows outside, making it negative
Identify effects of neurotransmitters
a neurotransmitter is a chemical signal that crosses the synaptic cleft and triggers a new signal
summarize the roles of the sensory division
gives information about internal/external information
describe different dunctions of neurons within the motor division
autonomic nervous system (involuntary)
1) sympthetic division (fight/flight)
2)parasympathetic division (rest/digest)
somatic nervous system (voluntary)
list six types of nutrients found in food
water, carbohydrates, fats, proteins, vitamins, minerals
summarize the four stages of food processing
ingestion: act of eating/drinking
digestion: process of breaking down food small enough for the body to absorb
absorption: absorbing of the small molecules and transporting the nutrients
elimination: when undigested material passes through the body
describe the tube in which digestion occurs
alimentary canal: a one way tube that is organized inot special regions that carry out digestion/absorption in a step-by-step process
trace the path of food through the organs of the digestive system
mouth–>esophagus–>stomach–>large intestine–>small intestine–>rectum–>anus
identify the organs and key functions of the circulatory system
blood: connective tissue made up of cells and liquid
heart: a multi-chambered muscular organ (overall flow of blood is from the heart to the tissues back to the heart)
blood vessels: where blood flows (circular tube structure)
explain how chemicals are exchanged between the blood and other tissues
the thin layer of epithelial that capillaries (microscopic blood vessels) consist of enables the diffusion of nutrients and oxygen out of the blood and the diffusion of waste products into the blood
relate the blood flow circuits to heart anatomy
the atrium(two upper chambers) receive the blood that is returning to the heart. the ventricles(two lower chambers) pump blood out of the heart. atria pumps blood into the venticles
explain heartbeat regulation
pacemaker sets the rate at which your heart contracts. It generates electrical impulses that spread rapidly over the walls of the atrium (making them contract). The impulses reach the AV node and then spread to the ventricles (making the contract)
explain how blood pressure is measure
(over) systole=state of contraction=higher #
(under) diastole=state of relaxation=lower #
identify the main components that make-up blood
red blood cells, white blood cells, platelets
describe the process of clotting blood
platelets adhere to the site of the damaged blood vessel. the platelets break apart and release clotting factors that make nearby platelets sticky and activate a series of reaction among other clotting factors in the plasma. The reactions form fibrin (protein) that threads up red blood cells and platelets. The threading builds up, dries, and forms a scab
list the organs of the respiratory system
pharynx, epiglottis, larynx, trachea, bronchi, lungs, brochioles, and alveoli
explain breathing and how it is regulated
moving air into and out of your lungs. you inhale when your diaphragm and rib muscles contract. You exhale when your diaphragm and rib muscles relax
describe the effects of smoking on the respiratory system
nicotine is absorbed once it reaches the brain it increases the level of dopamine (a neurotransmitter that controls pleasurable feelings). the nicotine will disappear quickly causing the body to crave it more
